TommyDS v2.2

• Removed tommy_list_remove_head_not_empty() as not used and wrongly
  implemented [Daniel Roethlisberger].

TommyDS v2.1

• Added a new hash function for strings: tommy_strhash_u32().
• Added a new tree implementation. It's not intended to be fast but useful if
  you need elements in order.
• Fixed some references to TOMMY_ARRAYBLKOF_SIZE, where instead
  TOMMY_ARRAYBLK_SIZE was incorrectly used [Rocco].

TommyDS v2.0

• Fixed a Segmentation Fault bug in the trie_inplace container when inserting
  duplicate elements.
• Faster array and hashlin implementation when accessing elements.
• Added new hashtable functions to iterate over all the elements.
• Added a new tommy_calloc() function used for allocating initialized memory.
  If you redefined tommy_malloc(), likely you have to redefine also tommy_calloc().
• Reached 100% code coverage in the regression test.
• Different source code organization.
• Added benchmark comparison with Binary Search Tesseract by Gregorius van
  den Hoven.